More About Genes - The Irish Really are a race apart By
Dr. Emmeline Hill

Men
with Gaelic surnames coming from the west of Ireland are
descendants of the oldest inhabitants of Europe. In a recent
study, scientists at Trinity College, Dublin, created a
new genetic map of the people of Ireland. By comparing this
map to European genetic maps they have shown that the Irish
are one of the last remnants of the pre-Neolithic hunters
and gatherers who were living throughout Europe over 10,000
years ago, before the invention of agriculture. The Irish
really ARE different.

What's
in a name?

Surnames
in Ireland have been passed from father to son for almost
1,000 years. The surname system in Ireland is thought to
exist as one of the oldest applications of the hereditary
surname system in the world. In Ireland this system was
not introduced but rather it is thought that toponymics
(names derived from place names) and nicknames were adopted.
For example, the name O'Callaghan comes from the Irish O'Ceallachain,
a diminutive of ceallach, which was taken to mean 'frequenter
of churches.'

Traditionally,
newly married women have taken up residence in the homeland
of their husband, meaning that family names have remained
in the area of the particular clans or septs for generations.
Surnames, except in the infrequent case of non-paternity,
are therefore an indication of family history, and on a
larger scale, of population history.

In
developing the new genetic map, the scientists studied the
DNA of 221 men from all over the country. The DNA was separated
into groups of people with names coming from the same area.
For example, names that originated in Ulster, such as Gallagher
and O'Reilly, were grouped together. Names from Munster
(e.g. Hogan, Meagher, Ryan); Leinster (e.g. Conlan, Phelan,
Rafter); and Connaught (e.g. Conway, Flynn, McHugh, Ruane)
were all grouped accordingly and were considered to be Gaelic
Irish. Also names of English (e.g. Harrison, Hill, Jacob,
Moore) Scottish (e.g. Hamilton, Johnston, Knox), Norman
(e.g. Barry, Bryan, MacNicholas) and Norse (e.g. Doyle)
descent were grouped separately. These were considered to
be non-Gaelic Irish. By separating the DNA as such, they
could study the genes that were present in a particular
region of Ireland over 1,000 years ago, when the surname
system was adopted.

The
science behind it

In
Issue 88 of INSIDE IRELAND, the article "Who are we? - It's
in the Genes" outlined the basic science behind genetic
studies of populations. Each cell in our body contains a
signature of our past. Modern technology allows us to look
directly at the amount of variation in the genes in these
cells. Variation accumulates over time through a random
process of mutation. Mutations occur at a constant rate.
Therefore, the more different two people are genetically,
the longer they have been separated.

Using
modern technologies to look at the differences between genes
in the different peoples of Ireland, the scientists in Trinity
College studied the genes on the Y chromosome. The Y chromosome
is the male-specific sex chromosome that is passed from
father to son in the same way that surnames are passed from
father to son.

A
distinct genetic pattern

By
performing a number of genetic tests the scientists were
able to identify a particular genetic pattern in the Y chromosome
of the Irish. An ancient genetic marker, known as haplogroup
1, was found in most Irish men. Scientists think that most
of the population of Western Europe carried this gene over
10,000 years ago. Over time however, through the movement
and mixing of peoples, this gene was diluted. Now it is
found in relatively fewer people throughout Europe.

The
greatest movement and migration of peoples in Europe has
been the movement of farmers from the south-east of the
continent after the invention of agriculture about 10,000
years ago. The farmers moved with their new technologies
north-west into Europe, probably displacing the local hunter-gatherer
populations that were living there at the time. In this
way the haplogroup 1 genes in Europe were diluted, the farmers
introducing new and different genes.

Men
with Gaelic names are more ancient

This
resulted in the formation of a gradient of haplogroup 1
genes throughout the continent, the lowest frequency of
these ancient genes being found in Turkey, and the highest
frequency in Ireland, with intermediate frequencies in continental
populations. In Ireland 78.1% of all men have the haplogroup
1 gene.

In
Ireland men with Gaelic names have higher frequencies of
this ancient marker than men with non-Gaelic names. For
example, men in Ireland with surnames of English origin
have 62% haplogroup 1 genes; men with Scottish names have
52.9% and men with Norman and Norse names have 83%. In Leinster,
73.3% of men with Gaelic surnames have this gene, in Munster,
94.6% and in Ulster 81.1%.

Connaught
men are the most Irish of the Irish

The
most striking finding was that in Connaught, the westernmost
point of Europe, almost all men (98.3%) carry this particular
gene. This means that the people of Connaught have been
relatively isolated, genetically, from the movements of
people that shaped the genetic makeup of the rest of the
continent. By comparison, in the east of the country there
has been a lot more mixing of genes coming from foreign
sources.

The
prevalence of ancient genes in Ireland suggests that the
Irish have largely maintained their pre-Neolithic genetic
heritage. There has been little genetic influence from outside
the country since the first people came to Ireland almost
9,000 years ago.

The
Early Bronze Age

By
looking at the amount of variation (the number of mutations
that have accumulated over time) in the haplogroup 1 genes
of these men it was possible for the scientists to estimate
a date for the origin of the bulk of these genes in the
country. They estimated that most of the genetic variation
in Ireland has accumulated over the past 4,200 years following
a rapid growth of the population at this time. This is the
time of the Early Bronze Age in Ireland.

The
Early Bronze Age in Ireland, among other things, saw the
appearance of megalithic tombs. Newgrange in Co. Meath is
the best known example. The scale and magnanimity of these
structures suggest that the creators belonged to a large,
highly socially evolved society.

The
scientists have shown most of the genes present in Ireland
today came from the people who were living at the time of
Newgrange. These people were the descendants of the ancient
hunter-gatherers of Europe.

Dr.
Emmeline Hill works at the Department of Genetics, Trinity
College, Dublin.